Despite treatment, cognitive and motor deficits are common in individuals with inherited urea cycle disorders. However, the extent to which the deficits involve specific cognitive or sensorimotor domains is unknown. Furthermore, little is known about the neurochemical basis of cognitive impairment in these disorders. This paper reviews studies of cognitive and motor dysfunction in urea cycle disorders, and discusses potential venues for investigation of the underlying neural basis that may elucidate these defects. Such methods of investigation may serve as a model for studying the relationship between genes, biochemical markers, brain function, and behavior in other metabolic diseases.